10-40. LetX1, . . . ,Xn depict a random sample drawn from the Poisson probability density function f (X; θ) = θXe−θ /X!, x = 0, 1, 2, . . . . It is known that T = ni

=1 Xi is a sufficient statistic for the mean θ > 0. Demonstrate that Tn

= X is an efficient statistic for θ.